Aside from being the one of the classic instruments in the history of modern music, what makes the Hammond C3 legendary ??? ... Laurens Hammon obtained a patent for the spring reverberator in 1939, and implements the original "T" spring reverb. Accutronics adapted this concept for the Electric Guitar amplifier in the 1960's and the rest is history.
A few maintenance and modifications to improve operation:
Lubricate the tonewheel synchronous motor (per service manual)
Direct input to console:
Connect shielded cable to 2EA "G" terminals on organ output
Run cable to 1/4IN input of ground lifting direct box (Rolls DB25)
Use low Z mic cable from direct box to console
Add grounded power cable with fuses (safety cover not shown)